In the medical field, syringes may be supplied ready for use or in the form of kits to be assembled, which may or may not be pre-filled with the liquid that is to be injected. Thus, the liquid that is to be injected is often supplied within a syringe body containing the dose that is to be injected. The end of the syringe body may be provided directly with a needle or may be provided with a syringe tip to which a needle support bearing the needle can be fixed. This syringe tip is, for example, of the “luer” or “luer lock” type. These syringes, syringe tips and needle supports are preferably “single-use” items so as to limit the risk of contaminating the patients and/or the care personnel with equipment that has already been used.
In this field, it is also of prime importance that the patients and users be protected from any risk of needlestick injury, particularly between the moment that injection is finished and the discarding of the injection device. Sleeves that protect the needles and that are activated manually after injection exist but in order to render the operation of protecting the needle more reliable and easier for the user, attempts have been made to render automatic the placement of the protective sleeve around the needle at the moment the needle is withdrawn from the injection site.
Document EP 409 180 describes a device for protecting a needle comprising a moving sleeve intended to cover the needle after injection. However, this protection device entails the sleeve rotating on itself by a certain amount in order to trigger its deployment, this rotation being performed while the distal end of the sleeve is in contact with the patient's skin, and while the medicinal product is being injected.
Thus, in such a case, because of the rotating of the sleeve, an undesirable feeling of friction against the skin and/or of instability of the injection device is perceived by the patient and/or by the user. This results in a notable impediment to the giving of the injection. As the injection cannot then be administered under optimal conditions, the patient and/or the user are reluctant to use the safety devices concerned and this often causes them to put themselves in unsafe injecting conditions. This solution is therefore not satisfactory.
There therefore remains a need for a device for protecting a needle, without additional manual intervention on the part of the user and which does not give rise to an effect of friction against the patient's skin.